The Saint Minimusheadlamp runs on a single 123A battery contained in a module that screws directly into the light assembly. Minimus produces a wide, variable-output beam optimized for your field of vision. Adjustment from 0 to 100 lumens is done with one hand—even cold or gloved—using a built-in variable light-output dial. Built from hard-anodized aerospace aluminum, Minimus is lightweight yet tough enough for the rigors of caving and mountaineering, and is submersible to 3 feet for up to thirty minutes. The fine-mesh headband features a moisture wicking Breathe-O-Prene® pad that provides unmatched comfort and dryness.